APA   Click to copy
Waqas, A., Khan, S., Sharif, W., Khalid, U., & Ali, A. (2015). Association of academic stress with sleeping difficulties in medical students of a Pakistani medical school: a cross sectional survey. PeerJ, 3, e840.

Chicago/Turabian   Click to copy
Waqas, Ahmed, Spogmai Khan, Waqar Sharif, Uzma Khalid, and Asad Ali. “Association of Academic Stress with Sleeping Difficulties in Medical Students of a Pakistani Medical School: a Cross Sectional Survey.” PeerJ 3 (2015): e840.

MLA   Click to copy
Waqas, Ahmed, et al. “Association of Academic Stress with Sleeping Difficulties in Medical Students of a Pakistani Medical School: a Cross Sectional Survey.” PeerJ, vol. 3, PeerJ Inc., 2015, p. e840.

@article{waqas2015a,
  title = {Association of academic stress with sleeping difficulties in medical students of a Pakistani medical school: a cross sectional survey},
  year = {2015},
  journal = {PeerJ},
  pages = {e840},
  publisher = {PeerJ Inc.},
  volume = {3},
  author = {Waqas, Ahmed and Khan, Spogmai and Sharif, Waqar and Khalid, Uzma and Ali, Asad}
}